Reciprocal latching ferrite phase shifter

ABSTRACT

A microwave phase shifter includes a pair of spaced ferrite toroids centrally positioned within a rectangular waveguide adopted to propagate TE10 microwave energy. Each of the ferrites has a square hysteresis loop characteristic and each is independently energized.

United States Patent Freibergs [54] RECIPROCAL LATCHING FERRITE PHASE SHIFTER [72] Inventor: Elmer Freibergs,

Branch, NJ.

[73] Assignee: The United States of America as represented by the Secretary of the Army 22 Filed: June 23,1970

21 Appl.No.: 49,106

West Long [52] US. Cl. ..333/3l A, 333/24.l [5|] Int. Cl. ..H0lp 1/18 [58] Field of Search ..333/24.1, 24.2, 3] A [56] References Cited UNITED STATES PATENTS 3,435,382 3/1969 Agrios et al ..333/24.l X

PULSE SOURCE 51 Aug. 1,1972

3,277,401 10/1966 Stern ..333/24.1 3,555,463 l/197l Ogasawara et a]. ..333/24.l X

OTHER PUBLICATIONS lnce et al., Nonreciprocal Remanence Phase Shifters in Rectangular Waveguide, IEEE Trans. on MTT, Feb. 1967 Primary Examiner-Paul L. Gensler Att0rneyHarry M. Saragovitz, Edward J. Kelly, Herbert Berl and Jack H. Stanley ABSTRACT A microwave phase shifter includes a pair of spaced ferrite toroids centrally positioned within a rectangular waveguide adopted to propagate TE microwave energy. Each of the ferrites has a square hysteresis loop characteristic and each is independently energized.

2 Claims, 1 Drawing Figure PULSE SOURCE RECIPROCAL LATCI-IING FERRITE PHASE SHIFTER The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

BACKGROUND OF THE INVENTION This invention relates to reciprocal microwave phase shifters and more particularly to waveguide type microwave shifters utilizing ferrites. One type of latching ferrite phase shifter well known in the art employs a shape in which the magnetic flux lines are closed, for instance, in the shape of toroids. A phase shifting device incorporating ferrite toroids has the advantage that in operation of the device no external holding electrical current is required to maintain the requisite magnetization state. Switching may be performed between two remanent states of magnetization by means of current pulses. The direction of the current pulses either reverse the direction of magnetization or leave it unchanged. The toroid material is conventionally disposed along the central longitudinal axis of rectangular waveguide propagating energy in the fundamental mode, referred to as the TE mode in the art. Heretofore, some of the problems effecting the operation of ferrite reciprocal phase shifters within waveguides included high dielectric loading, high insertion loss, higher order moding and high power pulsing requirements.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved microwave reciprocal phase shifter wherein the above-noted limitations are overcome.

In accordance with the present invention, there is provided a reciprocal microwave phase shifter which includes a rectangular waveguide for propagating microwave energy in the TE mode and a pair of spaced side-by-side ferrite toroids positioned longitudinally within the waveguide but with respective side arms of each toroid outside the side walls of the waveguide. Included further are respective current pulsing means coupled with each of said outside arms for independently energizing the toroids.

BRIEF DESCRIPTION OF THE DRAWING For a better understanding of the invention, together with other and further objects thereof, reference is had to the following description taken in connection with the single FIGURE of the accompanying drawing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, at there is shown a rectangular waveguide adapted to propagate conventional TE mode microwave energy. Longitudinally positioned in spaced side-by-side arrangement within waveguide 10 intermediate top and bottom waveguide walls 12 and 14 are two toroid sections 16 and 18 of identical construction and made of a suitable ferrite material capable of operating in the microwave frequency ranges. The ferrite material chosen must possess rectangular loop magnetization characteristics, preferably a square loop hysteresis characteristic. To-

roids 16 and 18 are preferably square in crosssection and are narrowly spaced apart by means of longitudinal dielectric separator 20 substantially centered between side waveguide walls 22 and 24. The dielectric constant of separator 20 is preferably the same as that of the ferrite material of toroids 16 and 18. As shown respective side arms 26 and 28 of toroids l6 and 18 are entirely outside the respective side walls of waveguide 10, are in parallel alignment, and are symmetrically beyond the waveguide side walls. The dielectric spacer 20 is preferably 0.002 inches thick and its width is the same as that of the thickness of the ferrite toroids l6 and 18. Arms 26 and 30 of ferrite toroid 16 are interconnected by end arms 34 and 36 that extend through side wall 24 of the waveguide to provide one closed loop magnetic path. Similarly, arms 28 and 32 of ferrite toroid 18 are interconnected by end arms 38 and 40 that extend through side wall 22 of the waveguide to form a second closed loop magnetic path. With the arrangement above, toroid sections 16 and 18 are positioned in a plane along the longitudinal axis of waveguide 10 symmetrically spaced from the top and bottom waveguide walls 12 and 14, with the inner or proximal spaced arms 30 and 32 positioned substantially at the longitudinal axis of waveguide 10. A first conductor winding 42 is coiled around exterior arm 26 of toroid l6 and has its terminals connected to a first pulsed D-C current source 46. Similarly a second conductor winding 44 is coiled around exterior arm 28 of toroid18 with its terminals connected to a second pulsed D-C source 48. Both the current sources 46 and 48 may be of the variable and reversible type. Since the ferrite toroid side arms 26 and 28 are outside the waveguide 10, the number of turns on the windings 42 and 44 does not affect the operation of the phase shifter.

Assuming a TE mode of electromagnetic energy propagating through waveguide 10, it can be seen that the strongest waveguide fields are concentrated at the proximal spaced arms 30 and 32 of the ferrite toroids 16 and 18 respectively. The side arms 26 and 28 of respective ferrite toroids l6 and 18 will have a negligible effect on the operation of the device inasmuch as they are located outside the waveguide 10. When the remanent flux flow is in the same direction along the inner proximal spaced toroid arms 30 and 32, as indicated by the solid arrows, large phase shifts per unit length may be achieved. By maintaining the flux in either of the inner toroid arms 30 or 32 constant and reversing the current in the other inner side arm as indicated by the dashed arrow, the degree of differential phase shift may be varied from a maximum to a minimum. The dielectric separator 20 isolates the remanent flux flow in one toroid from the remanent flux flow in the other toroid in which the remanent flux flow is switched back and forth to affect reciprocal phase shift. It is to be understood of course that latching is obtained by using the square loop hysteresis characteristic of the ferrite material.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A reciprocal microwave phase shifter comprising:

a rectangular waveguide section for propagating microwave energy in the TB mode,

a pair of rectangular ferrite toroids that are made of the same ferrite material and that are identical in construction, said toroids being spaced and magnetically isolated by a dielectric separator each toroid having a portion positioned longitudinally within said waveguide section in close proximity to the longitudinal axis of said waveguide section said portions of the respective toroids being on opposite sides of the axis and 

1. A reciprocal microwave phase shifter comprising: a rectangular waveguide section for propagating microwave energy in the TE10 mode, a pair of rectangular ferrite toroids that are made of the same ferrite material and that are identical in construction, said toroids being spaced and magnetically isolated by a dielectric separator each toroid having a portion positioned longitudinally within said waveguide section in close proximity to the longitudinal axis of said waveguide section said portions of the respective toroids being on opposite sides of the axis and being centrally between the wide walls of said waveguide section, each toroiD having a winding coiled about a side arm that is entirely outside said waveguide, and respective current pulsing means coupled to each of said windings for independently energizing said toroids.
 2. The microwave phase shifter in accordance with claim 1 wherein said ferrite toroids have a square loop hysteresis characteristic. 